238t LIFE OF But in the northern regions, as soon as the naked rock comes into contact with the air, a tissue of velvety fibres is formed, upon it, like a coloured spot, darken- ing gradually, and affording- the foundation for a new- stratum of the organic tissue. Where high forest trees now stand, frail lichens once covered the earth- less rock. The history of vegetable life, and its gra- dual distribution over the bare earth, has its epochs, like the history of the subsequent human race. But although the plenitude of life is everywhere developed, although organization is ceaselessly working to reunite the elements, released by death, into new forms, this plenitude of life and its renewal differs according to the difference of the zones. Nature is suddenly torpified in the frigid xono, for fluidity is the condition of life. Animals and plants are here buried for months in their winter torpor (except mosses and other cryptogainia). On a large surface of the earth only such organic creations have developed themselves as are capable of withstanding a, considerable absence of caloric, or a long inter- ruption of the organic functions. But the nearer wo approach the tropics, the more the variety and grace of form and colouring, the freshness and force of organic life increase. This may be doubted by those "who have never left our quarter of the world, or have neglected the study of geography. If we descend from our thick oak forest over the Alps or Pyrenees, to Italy or Spain, or cast a glance at the African coasts of the Mediterranean, we should easily form the erroneous opinion that absence of trees is a characteristic of hot climates. But then we forget that southern Europe bore a different aspect when. the Pelasgian or Carthaginian colonies first settled there; we forget that the early civilization of the human race dislodges the forests, and that the revolu- tionary spirit of nations gradually robs the earth of those ornaments which gladden us in the north, and which, more than any history, proves the infancy of our civilization.